Machine to Machine (M2M) Communication (Machine Type Communication)
M2M communication will be described below in brief.
As is implied from its appellation, M2M communication is communication between electronic devices, that is, communication between objects. While M2M communication typically refers to wired or wireless communication or communication between a human-controlled device and a machine, it refers particularly to wireless communication between electronic devices, that is, communication between devices. M2M devices are much inferior to general terminals in a cellular network, in terms of performance and capability.
Many terminals are located within a cell and may be categorized according to their types, classes, service types, etc.
For example, terminals may be classified into Human Type Communication (HTC) terminal and Machine Type Communication (MTC) terminal depending on their operation types. MTC may include M2M communication. HTC means signal transmission and reception based on a human decision, whereas MTC means autonomous signal transmission of a terminal without human intervention, which is periodic or event-triggered.
In case of M2M communication, the total number of terminals may be increased rapidly. M2M devices may have the following features according to their supported services:
1. a large number of terminals;
2. a small amount of data;
3. a low transmission frequency (may be periodic);
4. a limited number of data characteristics;
5. not sensitive to time delay; and
6. low mobility or fixed.
M2M communication may find its application in various fields such as protected access and monitoring, tracking and discovery, public safety (in the event of emergency or disaster), payment (a vending machine, a ticket machine, or a parking meter), health care, remote control, smart meter, etc.
Idle Mode
Idle mode is a mechanism of enabling a Mobile Station (MS) to periodically receive a downlink broadcast signal without registering to a specific Base Station (BS) even though the MS roams in a radio link environment where a plurality of BSs are deployed across a wide area.
In idle mode, an MS is just downlink-synchronized to receive a broadcast message, paging message only during a predetermined period, without performing all normal operations as well as HandOver (HO). The paging message indicates a paging action to the MS. For example, paging actions include ranging, network reentry, etc.
The MS or the BS may initiate the idle mode. That is, the MS may enter the idle mode by transmitting a Deregistration Request (DREG-REQ) message to the BS and receives a Deregistration Response (DREG-RSP) message in response to the DREG-REQ message from the BS. Or if the BS transmits a DREG-RSP message or Deregistration Command (DREG-CMD) message to the MS, the MS may enter the idle mode.
Upon receipt of a paging message directed to the MS during an Available Interval (AI) in the idle mode, the MS transitions to connected mode by network entry with the BS and transmits and receives data to and from the BS.